The primary goal of the Cellular Kinetics Section is to develop a better understanding of the kinetic behavior of normal and tumorous tissues and to use such information to design optimal forms of chemotherapy. Toward this end both animal studies and studies in patients have been undertaken. This year alterations in DNA synthesis induced by chemotherapy in normal and tumorous tissues have been studied after 5-FU, methotrexate, 5-azacytidine and adriamycin. Kinetic studies in patients with ovarian cancer after methotrexate therapy have been carried out. Flow microfluorometry studies of ascites and solid tumors from patients with breast and ovarian tumors have been sequentially analyzed after treatment. Additional studies include flow microfluorometry studies in diffuse histiocytic lymphoma as well as studies of intraperitoneal 5-FU studies in patients with ovarian cancer with malignant ascites. Cellular kinetic studies in an ovarian carcinoma murine tumor model are presently underway.